The Duwamish River, an industrial waterway, international port, and EPA Superfund site in Seattle, Washington, is still home or a migration corridor for many species, including the ecologically and economically important salmon. During the summer of 2007, we assessed the efficacy of shore restoration by directly comparing restored shore sites with unrestored sites adjacent to and across the river, as well as comparing among similar triplicates at different locations along the salinity gradient in the lower Duwamish. To determine the effects of restoration activities, fundamental abiotic (DO, pH, temperature, salinity, etc.) and biotic (plankton abundance and diversity) components of the aquatic system were measured at all sites. Given the relatively short time since shore restoration, we primarily expected to discover minor increases in DO and planktonic functional group diversity due to shore profile and vegetation improvement to reduce runoff.
Results/Conclusions
Results indicated all measurements increased in variance from lower salinity to higher salinity locations. DO was found to be significantly higher at restored sites compared to unrestored sites. Plankton abundance and diversity measurements were highly variable, with restored sites not consistently having greater abundance or diversity. These results are an initial assessment of differences in aquatic characteristics among the sites and suggest the need for further work to better elucidate relationships among abiotic and biotic components. However, these preliminary results suggest that shore restoration activities have been initially successful through slight increases in DO, thus potentially providing more viable rest and feeding spots for migrating salmon.
